ST. PETERSBURG, Fla. -- Tim Wakefield doesn't worry about why he is successful indoors against Tampa Bay. The knuckleballer is just happy it continued Monday night.

Wakefield continued his dominance over Tampa Bay, allowing four hits over seven innings as the Boston Red Sox blanked the Devil Rays 6-0 on Monday night.

"The ball seems to move a little more inside," Wakefield said. "I don't care to know why. I just know that it does."

Wakefield improved to 19-2 - including a 9-0 mark at Tropicana Field -- all-time against the Devil Rays. It's the most wins by any Tampa Bay opponent. Wakefield (15-10) struck out five and walked one, and moved into a tie for the major league lead in wins this season.

"It's like a wiffleball," Tampa Bay left fielder Carl Crawford said. "He knows what he's doing with it. If I move up, I noticed he throws a different kind of pitch. When I moved back, he threw a certain kind of way. He ain't just throwing down the middle."

Wakefield has a decision in all of his 25 starts, the first to reach that number since Jack McDowell posted decisions in his first 27 starts with the Chicago White Sox in 1993.

"He's tough to hit, especially when he's on because he throws you those pitches and you don't know where they're going," Red Sox shortstop and former Devil Ray Julio Lugo said. "You think they're going to go for a ball and they go for a strike."

Wakefield has not allowed a run in 15 consecutive innings. He has also blanked Tampa Bay 19 innings in a row.

"Right now I don't have any solid answers," Devil Rays manager Joe Maddon said. "He's throwing strikes with it and it's moving. Bad combination for us."

Wakefield did experience back tightness after the fifth, but doesn't believe it will be a problem.

"It's not going to be bad," Wakefield said. "It happened last time I was here too. I don't know if it's being on this mound, the bed at the hotel."

The Devil Rays lost for the sixth time in eight games and fell to 47-77, two games worse than they were at this time last year.

Mike Lowell hit a homer and drove in three runs, and Manny Ramirez had two RBI for the AL East-leading Red Sox, who are 11-8 in August. Ramirez has 39 RBI in 38 games since the All-Star break.

Boston designated hitter David Ortiz sat out. Red Sox manager Terry Francona is looking to give his regulars a day off, and the fact Ortiz is hitting .147 (5-for-34, one homer) against Tampa Bay left-hander Scott Kazmir was one factor in the decision.

"With David, it made more sense today," Francona said. "We're trying to piece it together where you don't go too far with a player and get him a day off."

Ramirez replaced Ortiz as the DH. Francona said Ramirez, the regular left fielder, might get Wednesday's game off.

Lowell put the Red Sox up 2-0 on a two-run double in the first. His solo homer off Kazmir (9-8) extended the Boston lead to 6-0 in the fifth. The blast ended Kazmir's stretch of not allowing a homer in nine straight starts.

Dustin Pedroia drove in a run with a single and Ramirez hit a two-run single to make it 5-0 in the second. Ramirez had just five hits in 37 at-bats against Kazmir before his hit during the second.

Kazmir gave up six runs and seven hits in 5 2/3 innings. He entered with a 13-inning scoreless steak and had allowed just one run in 25 innings over his previous four starts.

"I just have to let this one go," Kazmir said. "It's frustrating losing all the time."

Notes

• Wakefield has won all four of his starts this season against Tampa Bay.
• Ramirez, with 1,600 RBI, moved past Nap Lajoie into 28th place all-time.
• Kazmir struck out eight and walked four during his 108-pitch outing. He has 176 strikeouts this season, which broke the team record of 174 he set in 2005.
• Wakefield's consecutive decision streak is the longest by a Boston pitcher since Danny MacFayden opened the 1929 season with 26 in a row.